212 



ON THE DEVELOPMENT OF THE WING-YENATION 

 IN ZYGOPTEROUS DRAGONFLIli^S, WITH SPECIAL 

 REFERENCE TO THE CALOVTERYGID.F.. 



By R. J. TiLLYAUD, M.A., B.Sc, F.E.S., Science Research 

 Scholar in the University op Sydnky. 



(Plates xxxii.-xxxiv., and Text- figs. 1-6.) 



In a previous paper concerning the development of the wing- 

 venation in Dragonflies,* I dealt partly with the case of the 

 Zygoptera. At that time, no larvae of the family Calopterygidm 

 were available for study. As this family undoubtedly includes 

 the most archaic forms amongst the Zygoptera, it was clear that 

 the solution of the problems still outstanding must be sought for 

 within it. In indicating this in my former paper, I ventured 

 the statement that "the many forms of Calopterygid larval wings 

 will one day yield a wonderful harvest to the fortunate student 

 who has a chance of investigating them." The CalopterygidcK 

 are, however, nearly all tropical forms. Even if a collector with 

 the requisite knowledge could visit the places where they abound, 

 there still remains the almost insuperable difficulty of photo- 

 graphing the wing-trachese in the recently-killed larva. The 

 apparatus required for this purpose is too costly and too cum- 

 bersome to be taken on an expedition of this kind. The larvae, 

 too, require running water to live in, and do not take kindly to 

 captivity. Hence they would not stand a long journey back to 

 a base suitable for operations. 



It seemed, therefore, that important problems awaiting solu- 

 tion might be indefinitely postponed unless some efforts were 

 made to obtain at least those Calopterygid genera that were 

 nearest to hand, In Australia, we have only one genus, Diphle- 



* "On some Problems concerning the Development of the Wing-Vena- 

 tion of Odonata." These Proceedings, 1914, xxxix, Part i., pp. 163-216, 

 Plates xi.-xii. 



